The invention relates to an anesthesia set for the receipt of an epidural catheter. The set includes an epidural cannula, and a spinal cannula. The epidural cannula, containing the mandrel, is provided at its distal end with a radial outlet opening for the epidural catheter and with an axial outlet opening for the spinal cannula.
Such an anesthesia set, known from DE 39 22 406 C1, consists of a substantially straight epidural cannula with an outlet opening, a spinal cannula which is longer and thinner than the epidural cannula and is insertable therein in such a way that it protrudes by its distal end from the epidural cannula, and an epidural catheter that can be pushed through the epidural cannula. The tip of the epidural cannula is bent, and the passage opening for the epidural catheter is oriented radially sideways. In the outer wall of the curvature of the tip, an outlet opening for the spinal cannula centered on the longitudinal center line of the epidural cannula is provided. This outlet opening is smaller than the outside diameter of the epidural catheter.
Handling of the known anesthesia set is easy for the user only if the tip of the spinal cannula positively enters the spinal canal in a straight line and if the epidural catheter can positively be introduced into the epidural space. While such introduction of the epidural catheter presents no problem in principle, special precautions are required--as the spinal cannula is much thinner than the epidural cannula--for the proper insertion of the tip of the spinal cannula into the spinal canal, so that especially the tip of the spinal cannula will not miss the axial outlet opening in the epidural cannula.
It has been proposed, therefore, for the known anesthesia set to attach on the spinal cannula, in spaced relation to its tip, a coaxial guide ring whose outside diameter is slightly smaller than the inside diameter of the epidural cannula. Because such a guide ring is obviously unable to prevent an oblique position of the spinal cannula inside the epidural cannula, it is recommended, for improving the guidance, to form the guide ring as a circumferentially closed circular-cylindrical tube, preferably consisting of a plastic hose which is to extend over the full length of the spinal cannula, leaving free a cannula section near the tip. The secure guiding and positioning of the spinal cannula thus requires considerable additional expenditure, by which the cost of manufacture of the known anesthesia set is increased.